Page 85 - DMGT404 RESEARCH_METHODOLOGY

Unit 4: Sampling Design

 Random sampling can be chosen by Lottery method or using random number table. Notes
 Samples can be chosen either with equal probability or varying probability.
 Random sampling can be systematic or stratified.
 In systematic random sampling, only the first number is randomly selected. Then by
adding a constant "K" remaining numbers are generated.
 In stratified sampling, random samples are drawn from several strata, which has more or
less same characteristics.
 In multistage sampling, sampling is drawn in several stages.

4.9 Keywords

Census: It refers to complete inclusion of all elements in the population. A sample is a sub-group
of the population.
Deliberate Sampling: The investigator uses his discretion in selecting sample observations from
the universe. As a result, there is an element of bias in the selection.
Multistage Sampling: The name implies that sampling is done in several stages
Quota Sampling: Quota sampling is quite frequently used in marketing research. It involves the
fixation of certain quotas, which are to be fulfilled by the interviewers.
Random Sampling: Simple random sample is a process in which every item of the population
has an equal probability of being chosen.

Sample Frame: Sampling frame is the list of elements from which the sample is actually drawn.
Stratified Random Sampling: A probability sampling procedure in which simple random sub-
samples are drawn from within different strata, that are, more or less equal on some characteristics.

4.10 Review Questions

1. What do you analyse as the advantages and disadvantages of probability sampling?
2. Which method of sampling would you use in studies, where the level of accuracy can vary
from the prescribed norms and why?

3. Shopping Mall Intercept Sampling is not considered a scientific approach. Why?
4. Quota sampling does not require prior knowledge about the cell to which each population
unit belongs. Does this attribute serve as an advantage or disadvantage for Quota
Sampling?
5. What suggestions would you give to reduce non sampling error?
6. One mobile phone user is asked to recruit another mobile phone user. What sampling
method is this known as and why?
7. Sampling is a part of the population. True/False? Why/why not?
8. Determine the sample size if the standard deviation of population is 20 and the standard
error is 4.1.
9. What do see as the reason behind purposive sampling being known as judgement
sampling?

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